Porcine intestinal yeast species, Kazachstania slooffiae, a new potential protein source with favourable amino acid composition for animals.

There is little information about Kazachstania slooffiae which dominates among other yeasts in the pigs' intestine. Therefore, the aims of this study were to characterise the yeast cell contents and to investigate which nitrogen sources, organic acids and alcohols may be utilised or produced by this species. The results showed that, K. slooffiae could use urea, ammonium sulphate, peptides and single amino acids and produce thereby ethanol and formic acid. However, this yeast did not metabolise amino acids, lactic, butyric, propionic and acetic acids as sole carbon source. Using a global metabolite profiling approach employing gas chromatography and high-resolution liquid chromatography mass spectrometry, was found that the amount of peptides and dehydroascorbic acid considerably increased in the fermentation residues after yeast cultivation. It is noteworthy that the cells of K. slooffiae had higher contents of nitrogen and total amino acids (especially lysine) than the cells of nutritional yeast (Saccharomyces cerevisiae). This study indicates that due to potential production of peptides and formic acid in the intestinal tract, K. slooffiae might have an impact on the gut health. Moreover, from a nutritional standpoint, the cells of this yeast can be a good source of protein with useful amino acid composition for animal.

Impact of diet composition on ileal digestibility and small intestinal morphology in early-weaned pigs fitted with a T-cannula.

Piglets, separated from their dam at 12 days of age and fed a milk substitute hourly, were used as a model for suckling. Animals were fitted with a terminal ileal T-cannula and a jugular vein catheter. At 28 days of age, half of the pigs had a dietary change to a cereal-based weaner diet fed as slurry, and the others remained on milk substitute. Animals were labelled by oral administration of 15N-labelled yeast for 10 days (days 15 to 25). Blood samples were taken twice a day to monitor 15N enrichment of the blood plasma. Diets included polyethylenglycol (PEG 4000) to allow calculation of apparent ileal digestibility of nitrogen and individual amino acids. Ileal bacterial nitrogen was calculated from D-alanine content of the digesta. Furthermore, small intestinal (SI) villus height and crypt depth were measured. Feed intake was increased by the dietary change. The total nitrogen flow was 3.2 ± 0.4 g/day and 5.9 ± 0.4 for the milk and weaner diet, respectively. Endogenous nitrogen flow at the terminal ileum was similar for both groups (milk diet 2.4 ± 0.4 v. weaner diet 2.2 ± 0.3 g/day), whereas the bacterial nitrogen content (0.08 ± 0.01 g/day milk diet v. 0.15 ± 0.01 g/day weaner diet, P < 0.01) and exogenous nitrogen flow (0.94 ± 0.16 g/day milk diet v. 3.29 ± 0.12 g/day weaner diet, P < 0.001) increased significantly in the weaner-diet group. The ileal apparent digestibility coefficient of protein was 0.81 ± 0.06 and 0.68 ± 0.01 for the milk replacer and the weaner diet, respectively. Morphology measurements made along the SI at 25%, 50% and 75% were similar between piglets fed milk replacer and those fed a cereal-based weaner diet. The only statistical effect (P < 0.01) of dietary change was an increase in crypt depth in the weaner-diet group. In conclusion, pigs, following a dietary change analogous to weaning, lack the capacity to fully digest a standard weaner diet. This may result in an increased nutrient content entering the large intestine and an altered microbiota. In the absence of a period of anorexia, often associated with traditional weaning, we saw no evidence of villous atrophy, but report here a significant crypt hyperplasia, especially at the 75% level, as a result of dietary change.

Investigations on the effects of dietary essential oils and different husbandry conditions on the gut ecology in piglets after weaning.

Essential oils (EO) are being considered as possible alternatives to in-feed antibiotic growth promoters in pig nutrition. The effects of an EO mixture consisting of limonene, eugenol and pinene (10.0, 2.0, and 4.8 mg/kg diet, resp.) on gut physiology and ecology were studied in piglets. The experiment was conducted at low (commercial farm) and high hygienic conditions (experimental farm), to elucidate interactions between EO supplementation and husbandry methods. Piglets were weaned at 28 days of age, when they were offered either a control diet (C) or C with EO. Four piglets were sacrificed in each group on day 29, 30, 33 and 39. Digesta from the third distal part of the small intestine and from the colon were sampled and analysed for pH, dry matter, lactic acid, short chain fatty acids and ammonia concentrations. Enterobacteria, enterococci, lactobacilli and yeast counts were obtained by plating. Genomic DNA was extracted from digesta and polymerase chain reaction-denaturing gradient gel electrophoresis was performed. Individual microbial communities were identified at each farm. Age affected the intestinal parameters. No effects of the EO with exception for a significant reduction in colon bacterial diversity at 39 days of age could be recorded at experimental farm.

Microbial community composition of the crop and ceca contents of laying hens fed diets supplemented with Chlorella vulgaris.

It is generally accepted that the intestinal microbiota plays an important role in sustaining health and productivity of animals. Chlorella vulgaris, a naturally occurring green microalga, is believed to influence performance and health, including bird reproduction and egg quality. The nutritive value of open or indoor cultured C. vulgaris depends upon the technological process used to treat the algal mass. In the present paper, it is presented and discussed how 2 differentially processed C. vulgaris powders (spray-dried: SD-CV; bullet-milled and spray-dried: BMSD-CV) affected crop and cecal microbiota in laying hens. Polymerase chain reaction-denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA gene fragments was applied. The diversity of the crop universal bacterial DGGE fingerprints was not affected (6.4 +/- 1.65, 5.4 +/- 1.19, and 5.5 +/- 1.35 in the control, SD-CV, and BMSD-CV, respectively). Most of the bands from the corresponding positions in the gels were closely related to Lactobacillus sp. The DGGE fingerprints of V2-V3 fragments of 16S rRNA of crop lactobacilli had lower diversity in the control hens (8.7 +/- 1.22) than in the SD-CV (9.2 +/- 1.77) and BMSD-CV (9.9 +/- 1.88); thus, feeding C. vulgaris resulted in increased lactobacilli diversity in crop. A band closely related to Lactobacillus ingluviei was present in 9 out of 12 hens in the control group but in only 1 bird in the SD-CV and in 5 out of 11 birds in the BMSD-CV, suggesting a negative effect of C. vulgaris on this lactobacillus. Feeding C. vulgaris to laying hens also resulted in increased bacterial community diversity in the ceca. No effect of the technological processing of the microalgae on the microbial diversity could be observed. The diversity of the ceca universal bacterial DGGE fingerprints was lower in the control group than in the SD-CV and BMSD-CV (5.6 +/- 1.72 vs. 9.16 +/- 2.64 and 9.31 +/- 2.41, respectively). Most of the sequences retrieved from the DGGE bands formed ceca that were closely related to Ruminococcaceae, Lachnospiraceae, and lactobacilli, giving further insight into still poorly discovered intestinal microbiota of laying hens.

Effect of a single oral administration of Lactobacillus plantarum DSMZ 8862/8866 before and at the time point of weaning on intestinal microbial communities in piglets.

The aim of this study was to evaluate whether a single administration of two strains of Lactobacillus plantarum (DSMZ 8862 and 8866) either before or at the time point of weaning can influence the intestinal microbiota of piglets. A total of 176 piglets were allocated into five groups: control (LP0), administration of 5 x 10(9) or 5x10(10) cfu at day 25 of life (LP1, LP2) and administration of 5 x 10(9) or 5 x 10(10) cfu at day 28 of life (LP3, LP4). Piglets were weaned on day 28 of life. On day 25 (LP1, LP2), 28 (LP0, LP3, LP4), 33 (all groups) and 39 (all groups) of life, 10-13 animals of each group were killed and genomic DNA was extracted from small and large intestinal contents. Denaturing gradient gel electrophoresis demonstrated that administration of L. plantarum had a significant effect in GIT microbial communities as revealed by the Simpson's index of diversity and cluster analysis based on the Dice similarity index; this effect was more pronounced in groups LP3 and LP4. A treatment dependent presence of Clostridium glycolicum-like, Lactobacillus sobrius-like, Eubacterium rectale-like and Roseburia faecalis-like phylotypes was observed. The results show that the administration of L. plantarum at the point of weaning can influence gastrointestinal microbiota in weaning piglets which may have positive results on gastrointestinal health.

Carbon and nitrogen content based estimation of the fat content of animal carcasses in various species.

The objective of this study was to explore whether the C and N content can be used to estimate the fat content of animal carcasses. Considering the mean C and N contents of body fat and body protein, the fat content (EE) [%] can be predicted from C and N values [%] according to the generally valid equation EE = 1.3038 x C - 4.237 N. The application of this equation to estimate the total fat content of all animal carcasses results in significant differences in fat content between predicted and measured values. Therefore, we derived specific equations for rats, pigs, cattle, sheep, broilers and mice to predict the fat content by dual linear regression analysis (y = EE [% DM], x1 = C [% DM], x2 = N [% DM]) based on measured fat, C, and N contents of animal body samples. The specific equations for different animals showed residual standard deviations of 1.55, 1.63, 1.12, 1.35, 1.85 and 0.92% fat for rats, pigs, cattle, sheep, broilers and mice, respectively.

Comparison of the enzyme-hydrolyzed casein, guanidination, and isotope dilution methods for determining ileal endogenous protein flow in the growing rat and pig.

The objectives of the two studies were to determine whether the guanidination and isotope dilution methods applied both by labeling the animal (15N-infusion method) and by diet (15N-dilution method) give similar estimates of ileal endogenous lysine (EL) and endogenous nitrogen (EN) flows, respectively, to that of the enzyme-hydrolyzed casein (EHC) method in the growing pig and to determine whether the guandination and 15N-dilution methods give similar estimates of EL and EN flows, respectively, to that of the EHC method in the rat. For the first study, the test diet contained guanidinated and enzymatically hydrolyzed casein (molecular weight < 5,000 Da), which was also labeled with 15N. Rats (n = 30; mean BW 178 g) and pigs (n = 6; mean BW 19.2 kg) received a preliminary EHC-based diet for 7 d. The test diet was then given to the rats and pigs on d 8. Digesta were sampled from the terminal 20 cm of ileum of killed animals. The EL flows determined using the guanidination method were lower than those determined using the EHC method (means of 298 vs. 382, and 214 vs. 287 microg/g of DMI, in the rat and pig, respectively; P < 0.05 for the rat and P < 0.01 for the pig). The EN flows determined with the 15N-dilution method were lower than those determined using the EHC method (means of 1,034 vs. 1,942 and 1,011 vs. 1,543 microg/g of DMI, in the rat and pig, respectively, P < 0.001 for the rat and P < 0.05 for the pig). In the second study, pigs (n = 6; mean BW 27 kg) were continuously infused via the jugular vein with 15N-leucine for 11 d. The pigs received an EHC-based diet (molecular weight < 5,000 Da) during this 11-d period, after which digesta were sampled at the terminal ileum under anesthesia. The EN flow determined using the 15N-infusion method (mean of 1,971 microg/g DMI) was higher (P < 0.01) than that determined using the EHC method (mean of 1,233 microg/g DMI). The guanidination method gave a lower estimate of EL flow than did the EHC method in both the pig and rat. The 15N-dilution method also gave a lower estimate of EN flow than the EHC method in the pig and rat, and the 15N-infusion method gave a higher estimate of EN flow than the EHC method in the pig.

Evaluation of mobile nylon bag technique for determining apparent ileal digestibilities of protein and amino acids in growing pigs.

The mobile nylon bag technique (MNBT) may offer a simple, rapid means for assessing ileal AA digestibility of pig feed ingredients. In the present study, the effects of washing bags recovered from digesta, the amount and fineness of feeds, and feed trypsin inhibitor activity on apparent ileal digestibilities (AID) of CP and AA were determined with the MNBT. Twenty-four ileorectal anastomosed pigs (Yorkshire x Chinese Black barrows, 30 kg initial BW), of which 12 were fitted with duodenal T-cannulas, were used. Not washing the bags recovered from ileal digesta resulted in a reduction (P < 0.05) in apparent ileal digestibilities of CP and AA determined by MNBT. Washing the bags for more than 4 min overestimated (P < 0.05) the apparent ileal digestibilities of CP and AA compared with those determined with the anastomosed pigs. Sample size and fineness of grinding also affected (P < 0.05) apparent ileal digestibilities of CP determined by MNBT. The apparent ileal digestibilities of CP determined by MNBT were reduced (P < 0.05) when sample size exceeded 0.75 g and when feed was ground through screens with a mesh size of more than 1.0 mm. The closest agreement between results obtained by MNBT and a conventional ileal digestibility assay occurred when 0.75 g of feed ground through a 1.0-mm mesh screen was used per bag and bags were washed for 2 min after retrieval from digesta. Further studies are warranted to investigate the use of the mobile nylon bag technique for predicting the ileal digestibilty of AA for feeds containing antinutritional factors.

Fat storage capacity in growth-selected and control mouse lines is associated with line-specific gene expression and plasma hormone levels.

OBJECTIVE: For a detailed understanding of the complex traits growth and fat storage, a dissection into single genetic entities is mandatory. Therefore, blood plasma concentrations of hormones and the expression of selected genes were measured in extremely differentiated mouse lines. Genes were selected as candidates which might influence the complex traits body weight and fat accumulation, and which are located in chromosomal regions recently identified to affect trait differences between the lines. SUBJECTS AND MEASUREMENTS: The mouse lines were selected for high body weight (DU6), high carcass protein content (DU6P) and unselected controls (DUKs). In the selected lines DU6 and DU6P, mean body weights at the age of six weeks were about twice as high as the DUKs, whereas total fat weight was increased 2.2-fold in DU6 mice compared to DU6P and 3.2-fold in comparison to DUKs. Blood plasma concentrations of insulin-like growth factor 1 (IGF-1), growth hormone (GH), insulin and leptin, were measured in all lines at three weeks and at six weeks of age. Expression patterns of the genes encoding growth hormone (Gh), insulin-like growth factor 1 (Igf1), lipoprotein lipase (Lpl), glycerolphosphate dehydrogenase 1 (GDC-1), and adipocyte protein 2 (Ap2) were analyzed by Northern blot hybridization. RESULTS: In line DU6, highly significant increased concentrations of insulin and leptin were observed at six weeks of age; at this stage, IGF-1 concentrations were elevated in the two selected lines compared to controls with maximal concentrations of IGF-1 and GH in DU6P. The amount of mRNA for GH in the pituitary gland, for Igf1 in the liver and for LPL in epididymal fat tissue was significantly elevated in the two selected lines compared to controls at the age of three weeks, but not at six weeks. IGF-1 and GDC-1 mRNA concentrations were significantly higher in the DU6 mice than in the DU6P (P < 0.01) and the DUKs (P < 0.001) mice examined at both ages. CONCLUSIONS: The results prove line-specific concentrations of the analyzed hormones and the transcription amounts of Gh, Igf1, GDC-1 and Lpl. The measured differences are either direct genetic effects or secondary changes, resulting from different food consumption.

Physiological approaches to determining gut endogenous amino acid flows in the mammal.

Endogenous nitrogen and amino acid losses are associated with the digestion process. Different methods can be used to distinguish between gut endogenous and exogenous amino acid flows. These methods include feeding N-free diets, the regression approach, the use of enzyme hydrolysed proteins coupled with ultrafiltration and the use of markers (e.g., homoarginine, enzyme hydrolysed casein, 15N-labelled protein, 15N-leucine). All of the methods described have their limitations, but they have allowed major advances to be made in the measurement and understanding of endogenous amino acid secretion, reabsorption, flow and excretion.

The fate of nitrogen from 15N-labeled nitrate after single intravenous administration of Na15NO3 in sheep.

The metabolic fate of nitrogen from 15N-labeled sodium nitrate has been investigated in four healthy Polish Merino ewes. 15N-labeled sodium nitrate was administered intravenously at the dosage of 400 micromol.kg(-1) body weight. Blood plasma and urine concentrations of nitrate, ammonia, and urea and 15N enrichment of ammonia and urea were estimated over a 50-h period following 15N-nitrate administration. Nitrate (NO3-) was slowly eliminated from the blood plasma, and the presence of NO3(-) in the blood plasma above the nitrate "background" was observed for 50 h. 15N enrichment of blood plasma urea already appeared at 15 min and reached the maximum 6 h after 15N-nitrate administration. The urinary excretion of nitrate occured during 50 h after 15N-nitrate injection; the total urine excretion of NO3(-) was 23.63+/-2.39% of the administered dose. The mean urinary recoveries of nitrogen as 15N-urea and 15N-ammonia were 14.76+/-1.32% and 0.096+/-0.015% of the administered 15N-nitrate dose, respectively. It should be pointed out that in total only 38.49% of the administered nitrate-N was excreted in urine (as nitrate, ammonia and urea nitrogen) during 50 h. The results obtained indicate that sheep are able to store nitrate nitrogen in their body. The fate of the remaining approximately 60% of the 15NO3(-) administered dose is unknown. The results obtained do not allow one to conclude what fraction of the unrecovered approximately 60% of the 15NO3(-) dose was utilized by gastrointestinal microorganisms, and (or) metabolized, or stored in sheep tissues.

Evaluation of the 15N-isotope dilution technique for determining the recovery of endogenous protein in ileal digestion of pigs: effect of dilution in the precursor pool for endogenous nitrogen secretion.

Three barrows, average initial BW of 35 kg, were fitted with a re-entrant cannula at the distal ileum and catheters in each of the external jugular veins. The barrows were fed twice daily a diet containing barley as the sole source of protein. A 1-d intravenous infusion of saline was followed by an 8-d continuous infusion of [15N]leucine at a rate of 30 mg/(kg BW x d). Blood samples, taken hourly for 9 d, were pooled over the 12-h period between feeding. Ileal digesta were collected hourly on d 3 and 8 of the [15N]leucine infusion and pooled over 12 and 24 h. Enrichments (atom percentage excess 15N) in nitrogen (N), leucine, isoleucine, valine and alanine were measured in the trichloroacetic acid (TCA)-soluble and -insoluble fractions of plasma and in ileal digesta. Although the enrichments in N were similar in all pools, enrichments in amino acids in the TCA-soluble fraction of plasma were at least twice that in the TCA-insoluble fraction and in ileal digesta. The estimated contributions of endogenous N and amino acids to total N and amino acids in ileal digesta were 82.3 +/- 9.38, 39.0 +/- 3.83, 43.8 +/- 6.50, 51.9 +/- 3.24, and 51.9 +/- 9.80 for N, leucine, isoleucine, valine and alanine, respectively. The results from this study indicate that enrichments in total N in the TCA-soluble fraction of plasma may not accurately reflect enrichments in endogenous N secreted into the intestinal lumen. This factor should be considered when using the 15N-isotope dilution technique to estimate the recovery of endogenous protein in ileal digesta of pigs fed protein-containing diets.

Morphometry of the small intestine in pigs with ileo-rectal anastomosis.

Ileo-rectal anastomosis (IRA), which is frequently used to measure prececal digestibility in pigs, could induce some disturbances of the normal absorptive function. Our aim was to investigate the effects of different IRA surgical procedures on the main histologic characteristics of the small intestine in pigs. The 4 different IRA procedures compared to intact pigs (INT) were the following: either end to end (EE) or end to side (ES) with or without preservation of the ileocecal valve (EEV, EE, ESV, ES respectively). At 147 d after surgery, samples of the wall of the duodenum, jejunum and ileum were taken under anesthesia and histometric examinations were performed on HE- and PAS-colored sections to estimate changes mainly of mucosa and muscle layers. The values recorded for villus length, crypt depth, and whole thickness of the mucosa suggested that the EE procedures disturb the small intestine less than the ES models. A new parameter, called epithelial quotient and calculated as [(villus length/crypt depth)/mitotic index], was proposed to improve the comparisons. According to this quotient, EE procedures did not significantly affect the mucosa of the whole small intestine. An increased density of goblet cells was recorded in all operated pigs along the small intestine, but mainly in the ileum after EE-IRA. The lymphatic follicle area was reduced. These findings, which were in agreement with a reduced mitotic index in the ileum of EE-pigs, indicated a decreased effect of noxious factors on the small intestinal mucosa in IRA-pigs, especially after the EE-IRA procedure. Some atrophic or hypertrophic effects on the muscle layers were related to the absence or preservation of the ileo-cecal valve. Finally it was concluded that i) there was no major disturbance after IRA, and ii) the end to end procedure was most beneficial for the structural integrity of the small intestine.

Effect of level of dietary neutral detergent fiber on ileal apparent digestibility and ileal nitrogen losses in pigs.

A study was conducted with 20 barrows (average BW 25 kg) to determine the effect of various levels of neutral detergent fiber (NDF) in the diet on the apparent ileal nutrient digestibility and ileal diaminopimelic acid (DAPA) content, and consequently on the amount of ileal endogenous nitrogen. The pigs were fitted with a post-valvular T-cecal cannula. They were fed .8 kg/d of a corn starch-based semisynthetic diet formulated to contain equal amounts of protein and starch and 0, 60, 120, or 180 g of purified NDF/kg of diet, included at the expense of glucose. The purified NDF (pNDF) was isolated from wheat bran using an incubation procedure with pancreatin. Ileal digestibility of NDF was approximately 17% and was independent of the pNDF level in the diet. By increasing the amount of pNDF in the diets, apparent ileal digestibilities of dry matter (DM), nitrogen (N), neutral detergent insoluble N (NDF-N), and ash decreased linearly (P < .05). The DAPA content of the ileal digesta (g/d) was not affected by the percentage of pNDF in the diets. Calculation of the ileal bacterial N excretion indicated that more than 50% of the ileal N was of bacterial origin. With increased percentage of dietary pNDF, both endogenous and exogenous N in ileal chyme were linearly increased (P < .05). Thus, an increase in the dietary fiber content leads to a decreased apparent ileal protein digestibility due to increased ileal losses of both endogenous and exogenous protein.

[The prececal digestibility of corn, sunflower, cottonseed, linseed and soybean extract meal in swine with ileocecal anastomoses]. / Untersuchungen zur präzäkalen Verdaulichkeit von Mais, Sonnenblumen- Baumwoll-, Lein- und Sojaextraktionsschrot bei Schweinen mit ileorektal-Anastomosen.

Five pigs were each surgically prepared with end-to-side (E.t.S.) and end-to-end (E.t.E.) ileorectal anastomoses (IRA). The ileo-caecal valve was preserved in both modifications. The animals were fed diets with maize or solvent extracted oil seed meals from sunflower, cottonseed, linseed or soybean and maize in combination with one of these oil seed meals. The aim of the experiment was to estimate the influence of both IRA-techniques on the precaecal nutrient digestibility and amino acid (AA) absorption. The crude carbohydrate digestibility in two of the five single protein diets and in three of the four blends were significantly higher in the E.t.S.--than in the E.t.E.--IRA group. There were no significant differences between the two IRA-modifications in crude protein (CP) and crude fat digestibility. No differences were observed in AA absorption for the single components maize, sunflower- and cottonseed meal. The absorption values of isoleucine, leucine and valine from linseed meal were significantly more than 5%-units higher in the E.t.S.-group than in E.t.E.-animals. There were similar results in soybean meal for four essential AA but with differences below 5%-units. Accordingly the two IRA-modifications did not influence the AA absorption to a practically important extent.

Exogenous and endogenous contributions to nitrogen fluxes in the digestive tract of pigs fed a casein diet. III. Recycling of endogenous nitrogen.

The aim of the present study was to measure the incorporation of infused 15N in blood fractions, urine, digesta, faeces and in the exocrine pancreatic and biliary secretions, in order to estimate the endogenous part of nitrogen in the ileal digesta and in the faeces of pigs fed a casein diet and to calculate the total endogenous nitrogen secretion as well as its recycling in the digestive tract. For 8 d 11 Large White female pigs (50.1 +/- 1.8 kg) received a continuous infusion of L-[15N]leucine via a catheter in the jugular vein. The 15N-enrichment was measured in several fractions. The 15N-level of the pancreatic juice was higher than that in the biliary secretion, TCA-blood fractions, and urine during the whole experimental period. Using the 15N-isotope dilution method it was found that casein was completely digested up to the terminal ileum and that all the nitrogen in the ileal digesta was of endogenous origin. The total endogenous secretion was estimated at approximately 11 g N/d. The reabsorption of endogenous nitrogen amounted to 79% up to the end of the small intestine and 88% over the whole digestive tract.

True protein digestibility and amounts of endogenous protein measured with the 15N-dilution technique in piglets fed on peas (Pisum sativum) and common beans (Phaseolus vulgaris).

The faecal and ileal true protein digestibilities of the raw pea (Pisum sativum) varieties finale and frijaune and the ileal true protein digestibility of steam-processed common beans (Phaseolus vulgaris) were measured in piglets using the 15N-dilution technique. The faecal true protein digestibility of both pea varieties was about 97. The ileal true protein digestibility was between 93 and 95, indicating that the pea protein is almost completely enzymically digested in the small intestine. The faecal apparent protein digestibility was 85 for both varieties while at the ileal level it was 79 and 74 respectively. The lower ileal apparent protein digestibility of peas can be attributed completely to the excretion of endogenous protein. The ileal apparent protein digestibility of toasted common beans was about zero (-4); the ileal true protein digestibility was about 66. This indicates that the protein of the common bean, although toasted, was highly resistant to enzymic digestion. It was calculated that per kg ingested bean protein, 340 g undigested bean protein and 700 g endogenous protein passed the terminal ileum. The results of the present study explain why in previous experiments a strongly reduced weight gain and even weight loss was observed in piglets fed on raw and toasted common beans.

15N-leucine and 15N-isoleucine isotope dilution techniques versus the 15N-isotope dilution technique for determining the recovery of endogenous protein and amino acids in digesta collected from the distal ileum in pigs.

Twelve gilts, with an average initial BW of 38 kg, were fitted with simple T-cannulas at the distal ileum and two catheters in the external jugular veins. The animals were fed twice daily (0800 and 2000) 700 g of one of four diets containing either soybean meal, canola meal, wheat, or barley as the sole protein source. 15N-leucine was infused continuously for 9 d at a rate of 40 mg/kg of BW daily via one of the jugular catheters. Blood samples were taken during feeding. Ileal digesta samples were collected continuously for 24 h on d 7 and 9 of the infusion period. 15N-enrichment excess in leucine and isoleucine in the trichloroacetic acid (TCA)-soluble fraction of blood and in digesta were measured using single-ion monitoring gas chromatography-mass spectrometry. Assuming that the 15N-enrichment excess in leucine and isoleucine in the TCA-soluble fraction of the blood is similar to that in endogenous protein secreted into the digestive tract and that the amino acid composition of endogenous protein is constant, the contribution of endogenous to total protein in ileal digesta was calculated using the 15N-isotope dilution technique for leucine and isoleucine, respectively. These contributions were much smaller for the 15N-leucine than for the 15N-isoleucine isotope dilution technique: 7.1 to 11.0 vs 21.8 to 24.9 g of protein/kg of DM intake. The values obtained with the 15N-isoleucine isotope dilution technique were close to those obtained with the 15N-isotope dilution technique as described in a previous publication.

[The use of the mobile bag technique in swine. 2. Determination of the apparent and true crude protein digestibility of 15N-labeled feed]. / Untersuchungen zur Anwendung der mobilen Beuteltechnik bei Schweinen. 2. Mitteilung--Bestimmung der scheinbaren und wahren Rohproteinverdaulichkeit von 15N-markierten Futtermitteln.

In a series of experiments in two ileo-rectostomized pigs the precaecal apparent and true digestibilities for crude protein of seven 15N-labelled feedstuffs were studied using the mobile bag technique. True digestibility values of crude protein calculated with the help of isotope dilution were 4-14 units higher than the corresponding apparent digestibility values. This is caused by the infiltration of the bag residues with endogenous unlabelled nitrogen. In dependence on the kind of feedstuff the endogenous N portion in the bags amounted to 25-70% of the total N. In addition, the contamination is influenced by differences between the animals (mean 4-7%) and by different treatments of bags after gut passage (3-10%).

[Comparison of methods for determining the prececal nutrient digestibility and amino acid absorption of swine with ileorectal anastomoses and ileocecal bridge cannulas]. / Methodenvergleich zur Bestimmung der präzäkalen Nährstoffverdaulichkeit und Aminosäurenresorption zwischen Schweinen mit ileorektal-Anastomose und ileozäkal-Brückenkanüle.

The apparent precaecal nutrient digestibility and amino acid (a.a.) absorption of 10 diets were estimated in pigs with end-to-side ileorectal anastomoses (IRA) as well as with ileocaecal re-entrant cannulae (IZB). The digestibilities of organic matter and crude carbohydrates were significantly higher in IRA pigs than in IZB pigs in two resp. three diets only. There were no practical important differences for the digestibilities of crude protein and crude fat in all diets. Out of the 180 a.a. absorption comparisons only 20 (i.e. 11%) showed differences larger than 5%-units. The absorption rates of several a.a. were lower in IRA than in IZB pigs and of some other a.a. on the contrary. The methionine absorption of five legume diets and one barley + lysine diet were up to 15% resp. 4%-units lower in IRA pigs. Possibly this was due to the activity of microbes in the rectum in connection with a small intake level of protein bound methionine. In order to minimize such a falsification it is proposed to use the end-to-end anastomosis. The deviations in the apparent a.a. absorption between IRA and IZB pigs can be explained partly by differences in the quantity of precaecally excreted endogenous a.a. per 100 g DM intake.